#include <iostream>
#include <type_traits>
int main() {
  using namespace std;
  cout << boolalpha;
  static_assert(is_null_pointer<decltype(nullptr)>::value ==
                true); // decltype(nulptr) 声明空指针类型，为 true
  static_assert(is_null_pointer<int *>::value == false);
  static_assert(is_pointer<int *>::value == true); // int* 指针类型
  static_assert(is_pointer<decltype(nullptr)>::value == false); // int* 指针类型
}
